March 10, 2012

Major Coastal Storm

Forget the snow showers and other minor weather annoyances.   We got bigger fish to fry.   A major cyclone will rapidly develop on Sunday and then move northward off our coast, crossing the northern portion of Vancouver Island.  A storm that will produce very strong winds and substantial waves along the Northwest coast, but pass far enough out to lessen the the threat of a major windstorm over most of the interior.

Here is the latest UW WRF forecast (12km domain) for 7 AM on Monday.  Most of the major modeling systems...including the ensemble systems...agree with this solution, so there is a good chance reality will be similar.  A very strong low center of 963 hPa, with intense pressure gradients around it.  Large gradients down the Strait and along the Oregon coast as well.  Shift this low 150 miles to the east and we would have real problems over Puget Sound.

Here is the forecast SUSTAINED wind speed (in knots) at the same time. 50 kts along the coast and well over 50 knots south and east of the low center.  That area is sometimes called the "poisonous tail of the bent-back occlusion."

Lets examine a zoomed in section for western Washington:  you can see there will very strong winds over NW Washington, particularly towards Victoria.  I don't know whether I would take the Victoria Clipper on Monday! (I bet they cancel). 50 kts and more (red) along the Washington coast.

As the low approaches Vancouver Island, the winds along the northern third will be extreme, with hurricane force gusts.  Here is the forecast at 10 AM Monday.  Wow.  Solander Island may well see winds over 100 mph.

Keep in mind that the low could shift east or west a bit from this forecast..but probably not much.

Of course, such a fierce storm will kick up substantial waves, although the rapidity of its development and its quick motion will work against the really big stuff.  Remember big waves require strong winds, with large fetch and long duration.  We have the first, but lack a bit in the second and third.  Here is the forecast from the NWS Wavewatch III model for Monday at 1 PM.  8-9 meter (26-29 foot) waves along the coast.  Not a good day to be fishing out there.  But a good one to head to the shore to watch big waves and to thrill in the winds. (Editorial Comment: I still believe we undervalue the value of storm tourism along the coast--and the attraction of a storm, tsunami, and shipwreck museum out there.  The coastal hotels and B&Bs should be packed on Sunday night with people ready to experience a big storm.  Why head to Oklahoma to see a tornado when you can view something grander and lots more dependable).

The amazing thing is that we can predict such storms.  Essentially it hardly exists now, and on Sunday it will develop explosively....we call such storms meteorological "bombs."   Here is a surface map (isobars...lines of constant pressure at the solid lines, colors are temperature) at 1 PM on Saturday and every 12 hrs so you can appreciate how quickly this event forms out of a minor trough:

Right now the incipient trough is WEST of the tip of the Aleutians.  Its extraordinary we can make these predictions...and be right so often.

And did I mention snow?  The mountains will get around a foot today and Sunday and several feet on Monday and Tuesday with this system.  No water problems for us next summer!


  1. Awesome post ... thanks. And I live in Tri-Cities.

  2. ...already getting some pretty good intermittent gusts out here in the San Juan's (6:30 pm Sat.).

  3. Thanks for the insights Cliff. Love your blog.

    I'm so ready for spring, but never expect to actually enjoy one here in the NW. This year seems no different.

  4. Love the detail in your blog. I come here daily to read your posts. Thanks for doing this. :)

  5. Awesome post x2 I live in Sooke on Vancouver Island the winds are staring to pickup along the straits of JDF

  6. Spring tides now, too. With a strong onshore push and low barometer, I expect higher than predicted tides. Well worth a look Monday morning here on Puget Sound

  7. As of 10 minutes ago, we have hard blowing snow in Ellensburg. Sun, 5:58pm....

  8. Dumping snow in ravensdale, black diamond and Enumclaw!!!! Road are getting slick!

  9. It's already gusting to at least 40mph here on Sinclair Island at 10:23pm. If this is any indication of where this is going it could be pretty intense by morning.

  10. Is this storm related to the terrific rainstorms Kauai had over the last 2 weeks - I was in Kauai for them - incredible rumbling thunder ALL NIGHT I know we get Pineapple Expresses, usually in November - Id love to see a satellite picture of how storms can track between the Pacific Northwest and Hawaii


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